In recent years, the panel display has developed rapidly, and has taken over the traditional CRT display gradually. The panel display generally includes: organic light-emitting diode display (OLED), plasma display panel (PDP), liquid crystal display (LCD), and field emission display (FED) etc. The thin film transistor (TFT) is one of the key components of the panel display, which is used as a switch device or a driving device of the panel display, for example, for controlling on and off of each pixel in the panel display.
FIG. 1 is a vertical schematic view of an existing metal oxide TFT. FIG. 2 is a sectional schematic view of the metal oxide FTF as shown in FIG. 1 at AB. The metal oxide TFT comprises a base substrate 1, a gate electrode 2 arranged on the base substrate, a gate insulating layer 3 above the gate electrode 2, an active layer 4 above the gate insulating layer 3, the active layer 4 being a metal oxide layer; a source-drain metal layer arranged above the active layer, the source-drain metal layer comprising a source electrode 5 and a drain electrode 6. However, the existing metal oxide TFT has the following problems in the actual application: the electric current in the metal oxide TFT in the working process is unstable; the electric current is too large such that the metal oxide TFT cannot be turned off, even seriously, the metal oxide TFT may also be burned.